talk to your laywer. there is probably some mistake in your paperwork or something that's not so clear or maybe the wrong people were left out/included in the process. European work laws can be complicated and not all hr people are on top of everything.

Helped me a lot a few years back and got me from "you are fired without severance" to "you are paid for six more months, you don't have to come in and here is half a year's pay in severance". Companies want to shock you into submission, hand it to an external party, lean back end enjoy.